For example, a plastic film punching apparatus is incorporated into a machine successively making plastic bags of plastic film, in which an aperture is formed in a plastic film. Japanese Laid-Open Utility Model Publication No, H06-5,898 discloses the apparatus including a female blade, a through hole being formed in the female blade. A male blade is moved toward the female blade to be inserted into the through hole so that a plastic film is sandwiched between and punched by the male and female blades, the aperture being formed in the plastic film.
In this case, the plastic film generates a waste when being punched, the male blade and the waste being inserted into the through hole, so that the waste must be adhered to the male blade. In this connection, in the apparatus, an air passage is formed in the male blade to eject air to the waste from the air passage, the waste being removed by the ejected air.
However, the waste is not always peeled off the male blade and removed by the ejected air when ejecting the air to the waste. Accordingly, the waste may be then withdrawn by the male blade pulled out of the through hole, to be mixed into the plastic film.
The through hole is thought to be a cause. The waste must be held in the through hole to be restricted from movement when ejecting the air to the waste. The waste would therefore be difficult to be peeled off the male blade.
By the way, Japanese Patent No. 3,655,627 discloses a machine for successively making plastic bags of plastic film, in which plastic films are fed longitudinally thereof and intermittently. The machine includes a heat seal apparatus and a cutter by which the plastic films are heat sealed with each other and cross cut when the plastic films are stopped temporarily whenever being fed intermittently, to successively make the plastic bags. The same is true of the plastic film punching apparatus incorporated into the machine. The plastic film is punched by the apparatus when the plastic film is stopped temporarily whenever being fed intermittently.
It is therefore an object of the invention to provide a plastic film punching apparatus in which the waste is removed reliably.